Olfactory responses are to be recorded from small twigs of the olfactory nerve, containing hundreds to thousands of these small fibers, and quantified with the integrator or moving-average technique, so prominently employed in taste studies. Response vs. concentration characteristics will be determined for selected odorants, including homologous chemical series. Slow potential responses (EOG's) from the olfactory mucosa and slow potential or wave responses from the olfactory bulb are to be related to the neural responses, if possible, from sites directly linked, anatomically. Experimental verification will be attempted of the belief that these relations can be manipulated with a number of procedures, which might be informative about stimulus and coding mechanisms. Unit primary and secondary responses will be studied in relation to the neural responses and behavioral responses will be studied similarily. Fish will be compared with air breathing animals such as turtles, frogs, birds and mammals. Regeneration of olfactory receptors will studied, in several of these animals after surgical intervention with the nerves.